Human babesiosis is a malaria-like illness due to infection of red blood cells by various species of protozoan parasites belonging to the genus Babesia. Most human infections reported in the United States are caused by B. microti which is endemic in parts of the northeast and north central United States. B. microti infections are often asymptomatic but can also progress to severe illness and even death, particularly in individuals who are immunosuppressed, asplenic or elderly. The parasite is transmitted primarily by the bite of the deer tick, however, it can also be transmitted by blood transfusion. More than 60 cases of transfusion-transmitted babesiosis have been identified over the last 40 years. During the past four years, there has been an alarming increase in the number of deaths due to transfusion-transmitted babesiosis. Hence, there is an urgent need to minimize the risk through development and implementation of a method for blood screening for Babesia.